Are you using console.log in your project? Are you tired of configuring
loglevel / winston / whatever to add timestamp, colors to your log messages?
Do you want a consistent log style?
This is the library for you! You can now log with style -- no configuration
required!
Works pretty much the same as loglevel, the only difference is that the exported root logger is preconfigured with loglevel-plugin-prefix and custom formatting functions in order to output nice colorful log messages with timestamp, log level and logger name.
const log = require('@monksoftware/monlog') log.trace(msg) log.debug(msg) log.info(msg) log.warn(msg) log.error(msg)
You can use this library without any configuration, it will use sensible defaults resulting in nice, useful and production-ready log messages:
- Millisecond-precision timestamp with timezone
- (optionally) colored loglevel
- Logger name
- Log only warnings and errors
const log = require('@monksoftware/monlog') const sublog = log.getLogger('SUB', log.levels.DEBUG) log.warn('You can have nice log messages in just one line!') sublog.debug("It's easy to define subloggers with different levels!") // [2019年02月18日T01:10:49.933+01:00] WARN [root]: You can have nice log messages in just one line! // [2019年06月04日T13:07:24.298+02:00] DEBUG [SUB]: It's easy to define subloggers with different levels!
const log = require('@monksoftware/monlog') // Default level is WARN, log.setDefaultLevel('DEBUG') const childLogger = log.getLogger('CHILD', 'DEBUG', { template: 'When: %t, who: %n, why: %l, what: ' }) log.info('Child logger has been set up') childLogger.debug('this is a debug message') childLogger.info('This is a info message') childLogger.warn('this is a warning message') childLogger.error('this is an error message') // [2019年02月18日T01:08:46.260] INFO [root]: Child logger has been set up // When: 2019年02月18日T01:08:46.262+01:00, who: CHILD, why: DEBUG, what: this is a debug message // When: 2019年02月18日T01:08:46.262+01:00, who: CHILD, why: INFO, what: This is a info message // When: 2019年02月18日T01:08:46.262+01:00, who: CHILD, why: WARN, what: this is a warning message // When: 2019年02月18日T01:08:46.263+01:00, who: CHILD, why: ERROR, what: this is an error message
You can use all loglevel-plugin-prefix customisations parameters:
const log = require('@monksoftware/monlog') const advancedLogger = log.getLogger( 'super-long-logger-name-maybe-too-much', 'DEBUG', { // Only use first letter of level, e.g. W for waraning logs levelFormatter: (level) => level.toUpperCase()[0], // Numeric timestamp timestampFormatter: (date) => +date, // Truncate logger names to 5 letters nameFormatter: (name) => name.slice(0, 5), template: `#%l# logger: %n - timestamp: %t - message:` } ) advancedLogger.info('I have strange taste for log messages...') // #I# logger: super - timestamp: 1559646093854 - message: I have strange tasted for log messages...
You don't. All applicaton logging should go to stdout and stderr. Log routing, dispatching and storage it's a deployment specific configuration and should therefore be in the hands of the sysadmin or be set up in the applicatoin packaging, it should not be decided by the applicaton source code. https://12factor.net/logs